Shrink sleeve for an article closure

ABSTRACT

The present invention provides a shrink sleeve for use on a closure of an article. The present invention does so by providing a decorated closure for an article, such as a container, used to package an item or items. The decorated closure includes a shrink sleeve and a closure for an article. The closure has a top end, a bottom end, and a side surface. The closure may further include a centerpoint of the top end and a centerpoint of the bottom end with a longitudinal axis passing therethrough. The shrink sleeve is shrunk around at least the side surface of the article, and the shrink sleeve is a laminate that includes a heat-activatable expandable layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 11/253,044, entitled “Shrink Sleeve for an Article Closure,”filed Oct. 18, 2005, the disclosure of which is incorporated byreference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates to shrink films for various articles, andin particular, to shrink sleeves for containers having closures.

BACKGROUND OF THE INVENTION

Shrink films, such as shrink sleeves and shrink wraps, are used inlabeling, often as an alternative to pressure-sensitive labels,heat-transfer labels, in-mold labels, and other labels. Shrink labelinginvolves sizing a shrink film, which may be a tubular shrink sleeve, toa particular article. Then one shrinks the film to snugly wrap thearticle within the shrink sleeve. The shrinking process is generallyaccomplished by the application of heat or steam to the shrink sleeve.Further processing may include heat-sealing any unsealed portions of theshrink sleeve and/or covering the article contents with a shrink cover.The material used for shrink films, such as a shrink sleeve, may dependon the shape and weight of the article and its contents. The shrinksleeve may be polyethylene terephthalate, polyethylene terephthalateglycol, polyvinyl chloride, or oriented polystyrene, for example. Thefilm has an inherent tension that is released by heating the film fromthe outside in a shrink oven. Shrink films may be produced in forms thatmay be oriented monoaxially (in a single direction). As the film cools,it shrinks snugly around the article. This shrinkage applies a veryslight pressure to the article, which aids in holding the shrink film tothe article.

Graphics, such as pictures, logos, and text for labels, may bereverse-printed on the shrink films and the shrink films then seamed,thereby forming a shrink sleeve. In general, shrink films arereverse-printed using flexographic and rotogravure printing technology.A master roll of shrink film is prepared with a number of label copiesacross its surface. The particular number of labels depends upon thesize of the label copy and the width of the master roll. The printedrolls are then slit-cut, thereby forming individual rolls containing onecopy of the label only. The slit rolls are then folded and overlapped,and seamed at the edge, forming a shrink sleeve that is wound on a core.The finished rolls are packaged and delivered to a particular locationwhere each of the shrink sleeves will be applied to an article. Theseshrink sleeves are commonly used for full body decoration andtamper-evident applications.

When a shrink sleeve is used in tamper-evident applications,perforations may be provided in the shrink film. Generally, theseperforations are provided on the shrink sleeve at a position that willbe proximal to an opening of the article being labeled. In such aposition, a portion of the shrink sleeve above the perforations willcontact and confront a closure of the article, and a portion of theshrink sleeve below the perforations will contact and confront a bodyportion of the article. In use, the closure, such as a cap on a bottle,is removed by applying a twisting or rotating force (i.e., a torsionalforce) to the closure. As this occurs, the torsional force is alsoapplied to the portion of the shrink sleeve confronting the closure ofthe article, while not being applied (at least without as much force) tothe body portion of the article. As a result, the closure and theportion of the shrink sleeve contacting the closure are removed from thebody portion of the article as the tamper-evident portion of the shrinksleeve (i.e., the portion contacting the closure) separates from theremainder of the shrink sleeve along the perforations. It is desirablethat the portion of the label below the perforations stay bonded to thearticle after the consumer opens the article. In order to preventslippage between the shrink sleeve and the body portion of the article,adhesives may be used to bond the body portion of the shrink sleeve andthe body portion of the article to one another.

However, while adhesives may be applied to the portion of the shrinksleeve that contacts the body portion of the article, they are notapplied to the portion of the shrink sleeve that contacts the closure ofthe article (i.e., the tamper-evident portion of the shrink sleeve“above” any perforation). This is because it is desired that the portionof the shrink sleeve confronting the closure be completely separatedfrom the closure and discarded. This prevents any shrink sleeve fromremaining on the closure where it could interfere with access to thecontents of the article, or interfere with reattachment of the closureto the article.

Further, since the portion of the shrink sleeve that confronts theclosure in tamper-evident applications is designed to be separated fromboth the closure and the remainder of the shrink sleeve, that portiongenerally is not labeled or otherwise decorated. Further, largeclosures, such as those found on containers of laundry detergent, ofteninclude ridges and grooves, which make it difficult for a label toadhere to the side surface of the closure. And, if any shrink sleevewere shrunk against such a closure, the shrink film would conform to themultiple ridges and grooves, thereby disrupting the appearance of anydecoration thereon. Of course, previously, this has not beenproblematic, since in tamper-evident applications, one does not want theshrink film to adhere to the side of the closure, and shrink films havenot otherwise been used on the side surface of closures.

While shrink sleeves have been used on closures in tamper-evidentapplications, other types of materials (nonshrink films) have been usedon closures for purposes other than tamper-evident applications. Forexample, pressure-sensitive labels have been positioned on the “land”(i.e., the top) of closures, such as caps for bottles. These labels mayinclude decorations and/or labels. However, labels, such as thedecorated pressure-sensitive labels, have not been applied to the sidesof closures for various reasons. One reason is that the side surfaces ofclosures often include features like ridges or flanges that disrupt theability of the label to adhere to, or otherwise associate with, the sideof the closure, and also may interfere with the presentation of anydecoration. Further, any label, such as the shrink sleeves describedabove, is easily separated from the closure due to the torsional forcesapplied when removing the closure from the container body. Thus, anylabel information is lost. Further, the appearance of an article havinga label or other decoration removed due to these torsional forces may beunaesthetic.

In view of the above, it would be desirable to provide a decoratedclosure for an article having a shrink sleeve label that is associatedwith the side surface of the closure. Further, it would be desirable forthe shrink sleeve to have decorations that are visible and intelligible(even on irregularly-shaped closures). It would be further desirablethat such a decoration be impervious to torsional forces applied to theclosure during use.

SUMMARY OF THE INVENTION

The present invention overcomes and eliminates the drawbacks describedabove in the Background of the Invention. The present invention does soby providing a decorated closure for an article, such as a containerused to package an item or items. The decorated closure includes ashrink sleeve and a closure for an article. The closure has a top end, abottom end, and a side surface. The closure may further include acenterpoint of the top end and a centerpoint of the bottom end with alongitudinal axis passing therethrough. The shrink sleeve is shrunkaround at least the side surface of the article, and includes aplurality of layers, one of which may be a heat-activatable expandablelayer including a thermally expandable composition.

The heat-activatable expandable layer may include a plurality ofmicrocapsules containing the thermally expandable composition. Thisthermally expandable composition may include a “foaming” agent having aneasily volatilizable hydrocarbon, and a binder resin. When subjected tohigh temperatures during the process of applying a label, themicrocapsules rupture, and the thermally expandable composition “foams,”and can intercalate into the grooves defined by the ridges on a closure,such that the label can withstand even greater torsional forces appliedto the closure.

Additionally, the expandable composition can provide a texture to thelabel, and can raise or surround the graphics (i.e., an ink layer) ofthe label. Alternatively, the thermally expandable composition can bepatterned in such manner that, when activated, the resulting raisedtexture can itself appear in a pattern or a design, thereby furtheradding to the aesthetics of the label. The textured label can offeraesthetic benefits by matching the nonglossy texture of containermaterials along with imparting its own design, and can create afriendly-to-the-touch type of label. Thus, the textured surface of thelaminate, due to the thermally expandable layer, provides a morecomfortable and enhanced grip to the user.

Further, the thermally expandable composition can impart a thermalbarrier property to the label. Thus, the raised textured surface createsincreased resistance to heat loss, providing a thermal barrier shouldany heated materials be placed within the container, or should anymaterials within the container be subsequently heated.

Furthermore, since the expandable layer is heat-activated, it will berecognized that the textured attributes of the label are induced by heatas opposed to other stimuli (e.g., pressure). Since the use of heat isalready an integral part of labeling applications such as heat transferand shrink sleeve labeling, the labeled article would not have to besubjected to any additional processes. This is advantageous because anyadditional process steps would decrease label application throughput.

The present invention further provides an adhesive for applicationproximal to an inner surface of a shrink sleeve. In particular, thisadhesive may be applied to the inner surface of the shrink sleeve andmay be adapted to contact a surface of the closure. The adhesive bindsthe shrink sleeve to the closure such that it can withstand thetorsional forces generally applied during removal of the closure. Theadhesive also allows the shrink sleeve to withstand any linear forces,which may otherwise cause the shrink sleeve to be “lifted” off theclosure. Further, when bound, the shrink sleeve can withstand thetorsional forces generated during a filling and capping process (such aswhen closures are predecorated—prior to filling of the article—and thenattached to the article following filling).

Further, as described above, one problem with prior inks used on shrinksleeves is that the inks are of a formulation that can absorb theadhesive, thus detracting from the ability of the shrink sleeve toproperly adhere to a surface. This problem is especially pronounced in ashrink sleeve in contact with a portion of an article that is subjected,often repeatedly, to torsional forces (i.e., the closure). To eliminatethis problem, the present invention provides an ink having a formulationthat does not absorb any adhesive used. In particular, the ink mayinclude a nitro-acrylic based resin including a pigment comprising TiO₂,and a plasticizer having a wax additive. Further, the ink may notinclude calcium carbonate in its formulation.

Thus, using the shrink sleeve film, adhesive, and inks described above,the present invention also provides a laminate including a film for ashrink sleeve, an ink layer disposed on an inner surface of the shrinksleeve, and an adhesive layer disposed on the ink layer. The ink layer,as described above, includes a plasticized nitro-acrylic based resinincluding a pigment load (such as TiO₂), and a wax additive. The waxadditive promotes the adhesive layer to lay out smoothly on the surfaceof the ink layer, rather than seeping into the ink layer. This, in turn,promotes adhesion of the laminate to an article to which it is applied.Further, the ink layer, in certain embodiments, does not include calciumcarbonate. In an alternate embodiment, the laminate includes a film fora shrink sleeve, an ink layer disposed on or proximal to an innersurface of the shrink film, a heat-activatable expandable layer, and anadhesive layer.

Finally, the present invention also provides a method of applying ashrink sleeve over a closure for an article. The method includesproviding a shrink sleeve having an axis of symmetry and at least onedecoration visible on an outer surface of the shrink sleeve. One alsoprovides a closure for an article, the closure having a top end, abottom end, a side surface, and a longitudinal axis passing through acenterpoint of the top end and a centerpoint of the bottom end. Thearticle is oriented such that the longitudinal axis is substantiallyparallel to the axis of symmetry. The shrink sleeve is positioned overand around the closure such that at least a portion of the closure isdisposed within and substantially surrounded by the shrink sleeve. Andthe shrink sleeve is shrunk such that the shrink sleeve constrictsaround at least a portion of the side surface of the closure, therebypositioning the shrink sleeve such that the at least one decoration isvisible on an outer surface of the shrink sleeve. As the shrink sleeveis shrunk (such as by heat), the increased temperature may cause aheat-activatable expandable layer to “foam” and intercalate into anygrooves or other surface irregularities on a closure.

As a result of the present invention, brand recognition can be developedby including a shrink sleeve with decoration (such as a brand label) ona closure because the consumer's eye is drawn to the closure. Further,the present invention allows maximum use of the “real estate” on acontainer, since closures were not previously a surface used inlabeling. And further still, the use of the shrink sleeve on the closurereduces costs for a customer company by removing the need for a colorantfor the closure.

Additional characteristics of the shrink sleeve of the present inventionwill be apparent from the following detailed drawings and description ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention and,together with the general description of the invention given above andthe detailed description of the embodiments given below, serve toexplain the principles of the present invention.

FIG. 1A is a perspective view of a closure for a container;

FIG. 1B is a perspective view of a shrink sleeve including decoration,in accordance with the principles of the present invention;

FIG. 1C is a perspective view of the shrink sleeve of FIG. 1B placedover and shrunk about the closure of FIG. 1A, in accordance with theprinciples of the present invention;

FIG. 2A is a perspective view of the closure and shrink sleeve of FIG.1C used in conjunction with a container;

FIG. 2B is a cross-sectional view of the container, closure, and shrinksleeve of FIG. 2A;

FIG. 3 is a cross-sectional view of a shrink sleeve laminate inaccordance with the principles of the present invention; and

FIG. 4 is a schematic of the process of shrinking a shrink sleeve abouta closure in accordance with the principles of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the Figures, the present invention provides a labeledarticle 10 for packaging an item or items. This labeled article 10includes a shrink sleeve 12 and an article 10 including a closure 14. Inparticular, and referring to FIGS. 1A-1C, in a first aspect, the presentinvention provides a decorated closure 14 for an article 10, such as acontainer used to package an item or items. The decorated closure 14includes a shrink sleeve 12 and a closure 14 for an article 10. Theclosure 14 has a top end 16, a bottom end 18, and a side surface 20. Theclosure 14 may further include a centerpoint 22 of the top end 16 and acenterpoint 24 of the bottom end 18 with a longitudinal axis 26 passingtherethrough. As shown in FIG. 1A, the closure 14 includes a flange 28and screw threads 30 proximal its bottom end 18. It should be recognizedthat the closure 14 including flange 28 and screw threads 30 is merelyexemplary, and any type of closure 14 may be used.

As shown in FIG. 1B, the shrink sleeve 12 is formed from a shrink film13. The material used for shrink films, such as a shrink sleeve 12, maydepend on the shape of the closure 14. The shrink sleeve 12 may be apolyethylene terephthalate, polyethylene terephthalate glycol, polyvinylchloride, or oriented polystyrene, for example. The film has an inherenttension that is released by heating the film from the outside in ashrink oven. The film may be oriented monoaxially (in a singledirection). Decorations 32, such as pictures, logos, and text forlabels, may be reverse-printed on the shrink film and the shrink filmsmay be seamed, thereby forming the shrink sleeve 12 (as shown in FIG.1B). The shrink film may be reverse-printed using flexographic androtogravure printing technology, for example.

The shrink sleeve 12 is shrunk around at least the side surface 20 ofthe closure 14 of the article 10, and includes at least one visibledecoration 32 on a surface of the shrink sleeve 12. Such a decoration 32may be provided by various inks well known to those skilled in the art.These may be reverse-printed on or proximal to the inner surface 34 ofthe shrink films (i.e., the surfaces that will be applied toward thesurface of the closure 14). Alternatively, the inks may be applied on orproximal to the outer surface of the shrink films. “Applied on,” as usedhere, means there is direct contact between the inks and the surface ofthe shrink film. “Applied proximal to,” as used here, means thatalthough the inks are applied to the same side as a surface of theshrink film, it is not necessary that there be any direct contactbetween the inks and the surface (although there may be). For example,another layer, or layers, may be disposed between the inks and thesurface that the inks or inks are “applied proximal to.”

In the illustrated embodiment (as seen in FIGS. 1C and 2A), thedecoration 32 is visible to an observer on a side surface of the shrinksleeve 12, and thus the closure 14, once the shrink sleeve 12 isassociated with the closure 14, such as by being shrunk around theclosure 14. The decoration 32 of the illustrated embodiment is shown asbeing visible only partially circumferentially about the shrink film,and thus the closure 14. However, in alternate embodiments, anydecoration 32 may be present substantially about the entirecircumference of the shrink sleeve 12, and thus the closure 14. In stillother embodiments, the shrink sleeve 12 may provide a plurality ofvisible decorations 32 about a surface of the shrink sleeve 12. Thedecorated closure 14 of the first aspect of the present invention thusincreases the available decorating surface (such as for labeling) on anarticle 10 to areas previously unused. As discussed above in theBackground of the Invention section, prior to the shrink sleeve 12 ofthe present invention, labels were not provided on a side surface 20 ofa closure 14.

Further, and referring now to FIGS. 1C, 2A, and 2B, a substantialportion of the shrink sleeve 12 contacts and confronts the side surface20 of the closure 14. However, a portion 36 of the shrink sleeve 12 mayconfront the top surface of the closure 14. In particular, a portion ofthe top end of the shrink sleeve 12, in an amount of at least 1 mm, mayconfront the top surface of the closure 14. This contact occurs as theshrink sleeve 12 is shrunk against the closure 14. As the shrink sleeve12 is placed around the side surface 20 of the closure 14, the length ofthe shrink sleeve 12 may be greater than the vertical length of the sidesurface 20 of the closure 14. Thus, a portion of the shrink sleeve 12proximal the top portion of the shrink sleeve 12 extends past the sidesurface 20 of the closure 14. As heat is applied to the shrink sleeve12, it shrinks about the side surface 20 of the closure 14, and theextra portion 36 at the top shrinks to confront a portion of the topsurface of the closure 14. The portion 36 of the shrink sleeve 12 thatoverlies, and thus contacts, the top of the closure 14, may furtherassist in holding the shrink sleeve 12 to the closure 14. This may occurregardless of the presence of any adhesive 40 on or proximal to theinner surface 34 of the shrink sleeve 12.

Additionally, a portion of the shrink sleeve 12 may confront a bottomsurface of the closure 14 (although this embodiment is not shown in thefigures). In particular, a portion of the bottom end of the shrinksleeve 12, in an amount of at least 1 mm, may confront the bottomsurface of the closure 14. This contact occurs as the shrink sleeve 12is shrunk against the closure 14. As the shrink sleeve 12 is placedaround the side surface 20 of the closure 14, the length of the shrinksleeve 12 may be greater than the vertical length of the side surface 20of the closure 14. Thus, a portion of the shrink sleeve 12 proximal thebottom portion of the shrink sleeve 12 extends past the side surface 20of the closure 14. As heat is applied to the shrink sleeve 12 it shrinksabout the side surface 20 of the closure 14 and the extra portion at thebottom may shrink about a portion of the bottom surface of the closure14. The portion of the shrink sleeve 12 that overlies, and thuscontacts, the bottom of the closure 14 may further assist in holding theshrink sleeve 12 to the closure 14. This may occur regardless of thepresence of any adhesive 40 on or proximal to the inner surface 34 ofthe shrink sleeve 12.

In the illustrated embodiment, as shown in FIGS. 1C, 2A, and 2B, thebottom surface of the shrink sleeve 12 does not contact the bottomsurface of the closure 14 so as to overlie the bottom surface of theclosure 14. Rather, while a substantial portion of the shrink sleeve 12contacts and confronts the side surface 20 of the closure 14, it can beseen that a portion 38 of the shrink sleeve 12 confronts the flange 28of the closure 14. In particular, the bottom end of the shrink sleeve 12may be flush with and confront the flange 28 of the closure 14. Thiscontact occurs as the shrink sleeve 12 is shrunk against the closure 14.As the shrink sleeve 12 is placed around the side surface 20 of theclosure 14, it is positioned such that a portion of the shrink sleeve 12is flush the bottom of the side surface 20 of the closure 14. As heat isapplied to the shrink sleeve 12 it shrinks about the side surface 20 ofthe closure 14.

Referring now to FIG. 3, the decorated closure 14 further includes anadhesive 40 disposed proximal to an inner surface 34 of the shrinksleeve 12. “Disposed proximal to,” as used here, means that although theadhesive 40 is applied to the same side as a surface (i.e., the innersurface 34) of the shrink sleeve 12, it is not necessary that there beany direct contact between the adhesive 40 and the surface (althoughthere may be). For example, another layer or layers, such as an inklayer 42 (see FIG. 3), may be disposed between the adhesive 40 and thesurface that the adhesive 40 is “disposed proximal to.” In theillustrated embodiment, the adhesive 40 is disposed proximal to theinner surface 34 in a flood pattern. The adhesive 40 may have a coatweight in a range of about 0.5 lb./ream to about 1.25 lb./ream. A reamis typically 3000 ft². In alternative embodiments, the adhesive 40 maybe otherwise applied, such as in a pattern of adhesive droplets. Severaldifferent adhesives well known to those skilled in the art may be usedwith the shrink sleeve 12 described herein. These adhesives may includeethylene vinyl acetate-based resins, such as water-born EVA andsolvent-based EVA. In particular, the adhesive may be SeikadyneB42-1001, which is an EVA-based material with a wax package for slip.However, the adhesive layer 40 may include any materials known to thoseskilled in the art that provide a bond to such a closure. For example,alternatively, the adhesive layer 40 may suitably be composed of athermoplastic polyamide adhesive. A preferred thermoplastic polyamideadhesive is the reaction product of a diamine with a dimerized fattyacid, such as that available under the trade name VERSAMID 900 seriesfrom Henkel Corporation of Minneapolis, Minn. It has been foundadvantageous to combine this polyamide constituent with a nitrocellulosebase in adhesive layer 40.

During shrinking of the shrink sleeve 12 to the closure 14, temperaturesgenerally need to be high enough to cause shrinking of the film, and yetlow enough to avoid deforming, or otherwise damaging, the closure 14and/or article 10. Thus, the adhesive 40 needs to activate in atemperature range similar to the temperatures used to shrink the film.The adhesive 40 activates at a temperature lower than a temperature thatwould cause deformation of the closure 14 and/or article 10. In oneembodiment, the adhesive 40 may activate between about 140° F. and about190° F. Alternatively, the adhesive 40 may begin to activate at about140° F., and fully activate at about 190° F. After being shrunk againstthe closure 14, the shrink sleeve 12 may withstand up to about 135 inchpounds of torque without being separated from the closure 14.

Further, additional layers may be included with the shrink sleeve 12.Referring still to FIG. 3, the shrink sleeve 12 may include aheat-activatable expandable layer 41. This heat-activatable expandablelayer 41 assists in increasing the stability of the shrink sleeve 12 inits association with a closure 14 having ridges 43 and grooves 45 (seeFIG. 1) against any torsional force applied to the shrink sleeve 12 andclosure 14. Prior to the application of heat, the heat-activatableexpandable layer 41 is in a nonactivated, and thus nonexpanded, state.When in a heat-activated state, the heat-activatable expandable layer 41expands. The application of heat generally may occur during the processof applying the shrink sleeve 12 to the article 10, although it may beapplied at other times, such as during a post flaming process. Theheat-activatable expandable layer 41 may include various materials inorder to achieve expansion, and in a particular embodiment, includes aheat expandable composition including a binder resin and a solvent. Thebinder resin may be present in a range of about 50% by weight to about80% by weight of the expandable layer, and the solvent may be present ina range of up to about 20% by weight of the expandable layer.

The solvent, such as water, for example, is used with an emulsifyingagent to prepare an emulsion including the binder resin. Thisemulsifying agent may be a surfactant. In general, the binder resin isfragmentized, by methods well known to those skilled in the art. Thefragmentized binder resin is then emulsified using the surfactant andsolvent by methods also well known to those skilled in the art. Thefunction of the binder is to impart cohesive film strength andinterlayer adhesion within the laminate of the shrink film 13,heat-activatable expandable layer 41, and any other layers. Upon theapplication of heat, the expandable composition undergoes an expansiveor “foaming” effect. This expansive or “foaming” effect could bedisruptive to the other layers of the laminate of the shrink sleeve 12.Thus, the binder resin is useful to hold any layers adjacent to theexpanding layer to one another in order to maintain the integrity of thelaminate of the shrink sleeve 12, to prevent any such disruption.

Additionally, the heat-expandable composition may also include acolorant. The colorant may be present in a range of about 1% by weightto about 5% by weight of the expandable layer. One function of thecolorant may be to match the color of the heat-activatable expandablelayer 41 to the closure 14 receiving the shrink sleeve 12.

Another function of the colorant may be to facilitate the opacity of theshrink sleeve 12 itself. For example, the shrink sleeve 12 may include aremovable portion (not shown), such as a perforated portion, that couldbe used for a coupon or a piece of a game or promotion. The opacity ofthe shrink sleeve 12 is therefore important in preventing revealing theinformation printed on the removable portion. By using the colorant inthe heat-expandable composition, one may facilitate the opacity of theshrink sleeve.

The heat expandable composition of the heat-activatable expandable layer41 may further be disposed on an outer surface of a plurality ofmicrospheres. These microspheres may be present in a range of about 10%by weight to about 50% by weight of the heat-activatable expandablelayer 41. The microspheres are held together to form theheat-activatable expandable layer due to the binder resin of theexpandable composition on the outer surface of the microspheres. Themicrospheres are designed to rupture to allow expansion of the heatexpandable composition upon the occurrence of a particular event, suchas heating to a particular temperature. In order to rupture, themicrospheres may be constructed from an easily volatilizablehydrocarbon. In a particular embodiment, the microspheres may beconstructed from Foamcoat A7810 AY, commercially available fromSovereign Specialty Chemical, of Chicago, Ill. However, as will berecognized by those skilled in the art, the microspheres can beconstructed from any material, as long as the microspheres can beadaptable to rupture at the proper moment (such as due to a temperature)to result in expansion of the heat-activatable expandable layer.Additionally, the microspheres may include an interior compartment. Agas, such as isobutane, may be microencapsulated in the interiorcompartment encapsulated by the microspheres. The gas expands on theapplication of heat, causing the microspheres to rupture and theexpandable composition to expand.

Thus, in one particular embodiment, the microspheres may beheat-rupturable. In embodiments wherein the microspheres areheat-rupturable, they may be adapted to rupture at temperatures at orabove about 180° F. When subjected to temperatures above about 180° F.during the process of attaching the shrink sleeve 12, the microcapsulesrupture and the composition “foams,” causing the layer to expand. Theexpandable lacquer is the only layer that foams/expands when heated. Inparticular, the microcapsules rupture, releasing a gas, such asisobutane, which expands the coating. The material is then held in theexpanded state by the binder resin. By using microspheres that areheat-rupturable, the laminate is amenable to use in labels that aresubjected to heat during the application process, such as shrink sleevelabels. This may eliminate the need for a separate heating step.However, it will be recognized by those skilled in the art that thelaminate having a heat-activatable expandable layer 41 as in the presentinvention, may be used for other types of labels, such aspressure-sensitive labels.

The term “microencapsulated” or “microencapsulation” is to be taken tomean the packaging by encapsulation of certain liquids or solids in apaste form in an enclosed solid shell. The walls of the microcapsulemust be chemically inert to the contents of the capsule and must possessthe required stability with respect to the surrounding medium. Further,the capsules must be sealed and must be sufficiently fracture-resistantfor the application in question, and also sufficiently temperaturestable. The size of the capsules depends on the production process andextends from a diameter of about 2 microns to about a diameter of about30 microns; however, a size of about 2 to about 20 microns is mostlyused. In the microcapsules of the present invention, a substance thatmay be contained within the capsule is isobutane. The remainingexpandable composition (i.e., binder, surfactant, and water emulsion) iscoated on the outer surface of the microcapsules. Upon the applicationof heat, the isobutane causes the microcapsules to burst and alsoprovides the expansive “foaming” characteristic to the expandablecomposition.

The binder resin and solvent (and optional colorant) of theheat-activatable expandable layer 41 may be chosen from variousmaterials. For example, the binder resin may be chosen from acrylicbinders, vinyl acrylic copolymer binders, vinyl acetate homopolymerbinders, styrene acrylic binders, and phenoxy binders. Morespecifically, the acrylic binder may be selected from, but is notlimited to, the following Rhoplex binder resins, commercially availablefrom Rohm and Haas, of Philadelphia, Pa.: B15R, B60a, B85, B88, B959,GL618, GL623, HA12, P554, and SP100. Further, the vinyl acryliccopolymer binder may be selected from, but is not limited to, thefollowing Polyco binder resins, commercially available from Rohm andHaas: 3103NP, 3250, and 6107. Further, the vinyl acetate homopolymerbinder may be selected from, but is not limited to, the following Polycobinder resins, commercially available from Rohm and Haas: 2149A and2152. Further, the styrene acrylic binder may be selected from, but isnot limited to, the following binder resins, commercially available fromRohm and Haas: P308, P322, and P376. And finally, the phenoxy binder maybe, but is not limited to, InChem PKHW34, commercially available fromInChem Corporation, of Rock Creek, S.C.

The solvent may be chosen from any substance that is an efficientsolvent for the heat-expandable composition, but which also does notcause the microcapsules to rupture. Thus, the solvent may be chosen fromdistilled water and isopropanol, for example.

The colorant may include a nonionic water-based dye. However, it shouldbe recognized that this dye is merely exemplary. Other types of dyes maybe suitable for the present invention, such as anionic dyes. In oneparticular embodiment of the present invention, the colorant may beadded to the expanding layer to add “tint” to the textured portions ofthe shrink sleeve 12.

The laminate of the shrink sleeve 12 may further include a waxcomponent. The wax component may be in a separate wax layer (not shown)in the laminate of layers of the shrink sleeve, or alternatively, may bepart of another layer, such as the heat-activatable expandable layer 41.

The wax component may include various materials. Such materials mayresult in a matte finish or in a gloss finish. For examples of suitablematerials for a wax component, see U.S. Pat. No. 4,536,434, thedisclosure of which is incorporated by reference herein in its entiretyand U.S. Pat. No. 4,581,266, the disclosure of which is incorporated byreference herein in its entirety. The '266 patent describes an exemplaryformulation for the wax component, including paraffin and a montan wax,and which may also include a minor amount of microcrystalline wax. Inaddition to these waxes, the formulation may include a tackifying resinand suitable binder. With proper selection of tackifier resin, the totalamount of crystallinity of the paraffin wax can be reduced.

Paraffin wax, a petroleum derived product, typically has a molecularweight between about 254 to 450 and is composed essentially of linearsaturated hydrocarbons ranging from C₁₈H₃₈ to C₃₂H₆₆. Paraffinstypically have a melting point from about 110° F. to 150° F. (“Meltingpoint,” as used herein, refers to drop melting point).

Paraffin wax suitable for use in wax component is sold in various gradesthat differ chiefly in melting point. Commercial grades of paraffin waxthat may be used are commonly designated as refined, semi refined, andcrude grade waxes. Paraffin wax of refined grade is obtainable from anumber of sources, one of which is the Petrolite Corporation, BarecoDivision, of Tulsa, Okla.

The microcrystalline component may be composed of saturated hydrocarbonsof higher melting point than those of paraffin wax. Microcrystallinewaxes characteristically contain between about C₃₄H₇₀ to C₆₀H₁₂₀hydrocarbons having molecular weight between about 478 and 840.Microcrystalline waxes (microwaxes) are characterized by an increasedamount of branching; although they contain straight chain molecules,they are not as linear a saturated hydrocarbon as paraffin wax. Alsocompared to paraffin wax, they contain a greater portion of cyclic ringmolecules. The crystalline structure of the microcrystalline waxcontains predominantly malcrystalline and needle-like crystals havingvery small, undefined form when compared with the plate-like crystallinestructure of paraffin wax under the same magnification. Thus, thecrystalline structure of microcrystalline wax is small and irregularwhen solidified from the melted wax. In solvents, microcrystalline waxdiscloses no well-formed crystals of any size.

The classes of microwaxes vary principally in their melting point range.For example, the so-called hard microwaxes have a melting point betweenabout 190° F.-210° F.; the plastic microwaxes a melting point betweenabout 145° F.-175° F.; the emulsifiable crystalline waxes between about190° F.-225° F.; and modified microwaxes between about 165° F.-220° F.All of these various types of microwaxes may be employed in the presentformulation. An illustrative, commercially available microcrystallinewax that is particularly suitable in the present formulation isavailable under the Victory White trade name from the PetroliteCorporation.

The montan wax component for wax release layer 16 is a coal(lignite)-derived wax characterized by high concentration of montanicacid (C₂₈H₅₆O₂). A particularly suitable type of montan wax is anoxidized, esterified, partially saponified montan wax as disclosed inU.S. Pat. No. 3,616,015, herein incorporated by reference. Montan waxesof this type have melting points (drop points) typically between about50° F.-110° F., saponification values between about 25 and 150, acidvalues between about 5 and 40, and penetrometer hardness (ASTM-D5-52)below about 15 as measured with 100 grams for 5 seconds at 25° F. Thesemontan waxes also have relatively high melt viscosity. An illustrativeoxidized, esterified, partially saponified montan wax is available underthe trade name Hoechst OP or Hoechst X55 modified montan wax from theHoechst Chemical Company, Frankfurt, Germany. Hoechst OP modified montanwax has a drop point (ASTM D127) of 212° F.-221° F., a congealing point(ASTM D938-49) between 165° F.-175° F., an acid number of 10 to 15, anda saponification number of 100 to 115. Hoechst X55 has a drop point of208° F.-218° F., a congealing point of 167° F.-176° F., an acid numberof 10 to 15, and a saponification number of 90 to 110. These waxes havemelt viscosities of at least about 150 centipoise at a temperature ofabout 25° F. above their solidification point.

Referring still to FIG. 3, the invention may further include an inklayer 42 disposed proximal to the inner surface 34 of the shrink sleeve12. “Disposed proximal to,” as used here, means that although the ink isapplied to the same side as a surface (i.e., the inner surface 34) ofthe shrink sleeve 12, it is not necessary that there be any directcontact between the ink and the surface (although there may be). Forexample, another layer or layers may be disposed between the ink and thesurface that the adhesive 40 is “disposed proximal to.”

The invention of the illustrated embodiment thus includes an adhesivelayer 40 disposed proximal to the ink layer 42, such that the ink layer42 is disposed between the inner surface 34 of the shrink sleeve 12 andthe adhesive layer 40 (see FIG. 3). The ink layer 42 may further includea background white ink. Many labels include a background white ink asthe “last-down” ink to provide a contrast to the other graphics of thelabel. Thus, the background white ink is the ink of the ink layer 42that may directly contact any adhesive layer 40. While the backgroundink is described as a “background white ink,” it will be recognized thatthe background ink need not be white, but can be any other colordesired. As described above, one problem with inks used on shrinksleeves 12 previously is that the inks are of a formulation that absorbsthe adhesive 40, thus detracting from the ability of the shrink sleeve12 to properly adhere to a container side surface. Such a problem wouldbe especially pronounced in a portion of a container (i.e., the closure14) that is subjected, often repeatedly, to more severe torque and otherforces. Thus, the present invention further provides an ink forapplication to an inner surface 34 of a shrink sleeve 12, the ink havinga formulation that does not absorb the any adhesive 40 used. Inparticular, the ink may include a plasticized nitro-acrylic based resinincluding a pigment load (such as TiO₂), and a wax additive. The resinmay also be a nitro resin. The wax additive may be PTFE, for example.The wax additive promotes the adhesive layer laying out smoothly on thesurface of the ink layer, rather than seeping into the ink layer. This,in turn, promotes adhesion of the laminate to an article to which it isapplied. Further, the ink does not include any calcium carbonate.

The ink of the present invention thus eliminates the absorption problem.It will be recognized by those skilled in the art that the “backgroundwhite ink” is merely exemplary, and any ink that is going to contact theadhesive 40 can be prepared as an ink without calcium carbonate.Additionally, or alternatively, such ink may be prepared withplasticized nitro-acrylic-based resin with a pigment load (such asTiO₂), and a wax additive.

Thus, using the shrink sleeve film, adhesive 40, and inks describedabove, the present invention also provides a laminate 44 including afilm for a shrink sleeve 12, an ink layer 42 disposed on the innersurface 34 of the shrink sleeve 12, and an adhesive layer 40 disposed onthe ink layer 42. The ink layer 42, as described above, includes aplasticized nitro-acrylic based resin including a pigment (such asTiO₂), and a wax additive; and the ink layer 42 does not include calciumcarbonate.

Referring now to FIG. 4, the present invention also provides a methodfor providing a shrink sleeve 12 over an article 10 such that, in use,the shrink sleeve 12 will not slip or tear away from the closure 14 ofan article 10 with which it is associated. This method includes thesteps of first providing a shrink sleeve 12 generally as describedabove, which has an axis of symmetry 46.

The method of the present invention also includes providing a closure 14having a top end 16, a bottom end 18, a side surface 20, and alongitudinal axis 26 passing through a centerpoint 22 of the top end 16and a centerpoint 24 of the bottom end 18. This closure 14 is thenoriented such that the longitudinal axis 26 of the closure 14 issubstantially parallel to the axis of symmetry 46.

Next, the shrink sleeve 12 is positioned over and around the closure 14such that at least a portion of the side surface 20 of the closure 14 isdisposed within and substantially surrounded by the shrink sleeve 12.Finally, the shrink sleeve 12 is shrunken such that the inner surface 34of the shrink sleeve 12 constricts around a portion of the side surface20 of the closure 14.

In general, the method of the present invention also allows for applyingshrink sleeves 12, which may include labels, to closures 14 by movingthe closure 14 into proximity with a source of shrink sleeve 12 film,positioning a strip of tubular shrink sleeve 12 around each closure 14,and heating the shrink sleeve 12 to shrink it against the closures 14.Additionally, the method includes severing the shrink sleeve 12 betweenadjacent closures 14 to separate them into individual shrink sleeves 12,each associated with one such closure 14. In one particular embodimentof the invention, the shrink sleeves 12 are heat-shrunken on thearticles 10 using hot air in a shrink tunnel 48, through which theclosures 14 and associated shrink sleeve films 12 are moved.

In the illustrated embodiment of the present invention, the shrinksleeve apparatus includes a roll 50 from which the plastic shrink sleeve12 is dispensed, an air source 52, a mandrel 54, a cutoff device 56, anda shrink tunnel 48. In particular, a master roll 50 of shrink film isprepared with a number of label copies across its surface. Theparticular number of labels depends upon the size of the label copy andthe width of the master roll 50. The printed rolls 50 are then slit-cut,thereby forming individual rolls 50 containing one copy of the labelonly. The slit rolls 50 are then folded and overlapped, and seamed atthe edge, forming a shrink sleeve 12 that is wound on a core.

In operation, an article 10, such as a bottle including a closure 14, isguided underneath the air source 52 and mandrel 54. The mandrel 54 isaligned with the shrink sleeve film 12, which is obtained from the roll50. A shrink sleeve 12 is pulled from the roll 50 and is blown open intoits tubular form by air from the air source 52. This tubular shrinksleeve 12 is then positioned over and slipped past the mandrel 54 inorder to maintain its tubular form and to guide the shrink sleeve 12over the closure 14 of the article 10. In the present invention, as theclosures 14 are positioned proximal to the shrink sleeve 12 and mandrel54, they are positioned such that the longitudinal axis 26 of eachclosure 14 is substantially parallel to the axis of symmetry 46 of theshrink sleeve 12. After the shrink sleeve 12 is guided and positionedaround the closure 14, a cutoff device 56 is used to sever the shrinksleeve 12 from the remainder of the roll 50 of film. Next, the closure14 and the loose plastic shrink sleeve 12 proceed through the shrinktunnel 48, which shrinks the shrink sleeve 12 against the closure 14through the application of heat. The heat for shrinking may be providedby steam. Alternatively, heat may be provided by a hot air manifold.Also, heat may be applied by a combination of these methods, forexample, steam heat coupled with air movement. A constant heat may beapplied to the shrink sleeve 12 and closure 14. Alternatively, theshrink sleeve 12 and closure 14 may experience gradations of temperatureas they move through the shrink tunnel 48. In one embodiment, heat maybe applied to the shrink sleeve 12 and closure 14 at a temperature inthe range of about 140° F. to about 190° F. Such a shrink sleeveapparatus is commercially available from Nippon Automatic Fine MachineryCompany of Anaheim Hills, Calif.

The desired temperature within the shrink tunnel 48 depends upon anumber of factors, such as the speed at which the closure 14 and plasticshrink sleeve 12 are moved through the tunnel 48, and also theparticular composition and thickness of the plastic film. In general, inone embodiment, heat should be applied that will reduce the size of theshrink sleeve 12 from 40% to 70%.

Following shrinking, the closure 14 and shrink sleeve 12 may then becooled by subjecting the shrink sleeve 12 to ambient temperatures toallow for a gradual cooling process. Alternatively, the shrink sleeve 12may undergo other cooling steps, such as subjecting the shrink sleeve 12to cool air or liquid.

While the present invention has been disclosed by reference to thedetails of preferred embodiments of the invention, it is to beunderstood that the disclosure is intended as an illustrative ratherthan in a limiting sense, as it is contemplated that modifications willreadily occur to those skilled in the art, within the spirit of theinvention and the scope of the amended claims.

1. A decorated closure for an article, the article used to package anitem or items, the decorated closure comprising: a shrink sleeve; and aclosure for an article, said closure having a top end, a bottom end, anda side surface; wherein said shrink sleeve is shrunk around at leastsaid side surface of said closure, to contact and confront said sidesurface, and said shrink sleeve being a laminate comprising a pluralityof layers, said plurality of layers including a heat-activatableexpandable layer.
 2. The decorated closure of claim 1, wherein said topend includes a top surface, and a portion of said shrink sleeveconfronts said top surface of said closure.
 3. The decorated closure ofclaim 1, further comprising an adhesive applied proximal to an innersurface of said shrink sleeve.
 4. The decorated closure of claim 3,wherein said adhesive is applied in a flood pattern.
 5. The decoratedclosure of claim 3, wherein said adhesive is an ethylene vinylacetate-based adhesive.
 6. The decorated closure of claim 3, whereinsaid adhesive activates at a temperature lower than a temperature thatwould cause deformation of said closure.
 7. The decorated closure ofclaim 3, further comprising an ink layer disposed proximal to an innersurface of said shrink sleeve.
 8. The decorated closure of claim 7,wherein said ink layer includes a background ink comprising anitro-acrylic based resin including a pigment comprising TiO₂, and aplasticizer having a wax additive.
 9. The decorated closure of claim 8,wherein said background white ink does not include calcium carbonate.10. The decorated closure of claim 1, wherein said expandable layerincludes a composition comprising a binder resin and a solvent.
 11. Thedecorated closure of claim 10, wherein said binder resin is present in arange of about 50% (wt.) to about 80% (wt.) of said expandable layer,and said solvent is present in a range of up to about 20% (wt.) of saidexpandable layer.
 12. The decorated closure of claim 10, wherein saidcomposition further comprises a colorant.
 13. The decorated closure ofclaim 12, wherein said colorant is present in a range of about 1% (wt.)to about 5% (wt.) of said expandable layer.
 14. The decorated closure ofclaim 10, wherein said composition is associated with a plurality ofmicrospheres.
 15. The decorated closure of claim 14, wherein saidmicrospheres are present in a range of about 10% (wt.) to about 50%(wt.) of said expandable layer.
 16. The decorated closure of claim 14,wherein said microspheres include Foamcoat A7810 AY.
 17. The decoratedclosure of claim 14, wherein said microspheres encapsulate a gas. 18.The decorated closure of claim 17, wherein said gas is isobutane. 19.The decorated closure of claim 14, wherein said composition is disposedon an outer surface of said microspheres.
 20. The decorated closure ofclaim 14, wherein said microspheres are heat-rupturable.
 21. Thedecorated closure of claim 20, wherein said microspheres are adapted torupture at temperatures at or above 180° F.
 22. The decorated closure ofclaim 10, wherein said binder resin is chosen from acrylic binders,vinyl acrylic copolymer binders, vinyl acetate homopolymer binders,styrene acrylic binders, and phenoxy binders.
 23. The decorated closureof claim 10, wherein the solvent is chosen from distilled water andisopropanol.
 24. The decorated closure of claim 12, wherein the colorantis chosen from a nonionic water-based pigment dye and an anionic dye.25. The decorated closure of claim 1, said laminate further comprising awax component.